Genetic variation in Clivia miniata var. citrina

[摘要] English: The genus Clivia is from the African tribe Haemanthaceae and a member of the family Amaryllidaceae. Clivia is endemic to southern Africa. Yellow Clivia are mutations of the orange-red standard forms that have appeared spontaneously in both wild and garden populations. Yellow Clivia plants are rare and desirable and were described as Clivia miniata var. citrina. Hobbyists from around the world trade in these ornamental plants initiating entire enterprises. Although the yellow form occurs naturally, many yellow clones have arisen through cultivation. Clones passed on from breeder to breeder have acquired different names. For directed breeding purposes in a thriving industry it is important to identify genetically similar plants. The aims of this study were to evaluate existing microsatellites for Clivia miniata var. citrina, to determine if AFLP analysis can distinguish among different plants within the genus Clivia and to determine genetic relatedness between different plants of 'Vico', 'Giddy' and 'Natal Yellow' cultivars. Previous studies done on Clivia include RAPD analysis and SSR analysis for Clivia. Work done in this study presents a first report of AFLP and SSR fingerprint analyses on C. miniata var. citrina. SSR fingerprint analysis revealed that the existing four SSR primer combinations were not applicable for studies on C. miniata var. citrina. AFLP analysis was optimised using a total of 28 EcoRI / MseI primer combinations. Primer combinations were evaluated using six randomly selected Clivia plants based on number of generated fragments, ability to score generated fragments, ability to detect polymorphism and level of polymorphic fragments. Fragments generated using EcoRI+3 primers in combination with Mse+4 primer combinations conformed to the chosen criteria. Primer combinations E-ACC with M-CATC, E-AGC with M-CATC and E-AGC with M-CTGG were selected for further studies on Clivia. AFLP analysis using three preselected primer combinations on 72 Clivia plants was successful in detecting genetic diversity and determining genetic relationships within closely related cultivated Clivia plants. Relatively high levels of genetic diversity (35%), as expected from known pedigree and species data, existed among Clivia plants. Genetic diversity within C. miniata and C. miniata var. citrina plants was high at 27%. Plants available for scrutiny were all genetically distinct. However, based on known pedigree data, names allocated to plants might not be truly representative of the true origin of the plants (e.g. Vico Meristem plants). Material obtained from different breeders could be distinguished at DNA level (e.g. 'Giddy' and 'Natal Yellow' cultivars). AFLP analysis revealed that different flower coloured plants (Apricot, Blush, Peach, Orange and Yellow) as well as plants from the same geographic areas were distributed together throughout the dendrogram with only a few of a certain colour grouping together. Known Group 1 Yellow and Group 2 Yellow were also present throughout the entire dendrogram, although the majority of known Group 1 Yellow plants grouped together. Clustering of the different species of the genus Clivia agreed with known pedigree data and hybrids included with their parents clustered according to known pedigree data. The phylogenetic relationships of natural populations of C. miniata indicated that all C. miniata plants shared a common ancestor. Clivia miniata from the same geographical area grouped together in the cladogram. More data would be required to prove these observations for all Clivia. Taxonomic status of the C. miniata var. citrina would depend on the monophyly of yellow Clivia plants. Orange flowered forms should be included to determine the validity of the current taxonomic status of these groups.

[发布机构] University of the Free State